title: Calcium-dependent Ret activation by GDNF and neurturin.
abstract: Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) define a new family of neurotrophic factors that play crucial roles in survival and differentiation of various neurons. Recent studies demonstrated that GDNF and NTN use a multicomponent receptor system in which glycosyl-phosphatidylinositol (GPI)-linked cell surface proteins and Ret receptor tyrosine kinase function as the ligand-binding and signalling components, respectively. In the present study, we investigated the role of Ca2+ ions for biochemical and biological activities of Ret because Ret has a unique structure of the extracellular domain with the cadherin-like motif. The results demonstrated that Ca2+ ions might be required for the complex formation of Ret and GDNF or NTN that induces Ret oligomerization and autophosphorylation. Full morphological differentiation of neuroblastoma cells by these neurotrophic factors was also Ca2+-dependent. These findings thus suggested that, in addition to GPI-linked cell surface proteins, Ca2+ ions are components of the signal transducing complex formed by Ret and GDNF protein family.
authors.affiliation: Department of Pathology, Nagoya University School of Medicine, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Nozaki
authors.forename: N
authors.initials: N
authors.lastname: Asai
authors.forename: H
authors.initials: H
authors.lastname: Murakami
authors.forename: T
authors.initials: T
authors.lastname: Iwashita
authors.forename: Y
authors.initials: Y
authors.lastname: Iwata
authors.forename: K
authors.initials: K
authors.lastname: Horibe
authors.forename: R D
authors.initials: RD
authors.lastname: Klein
authors.forename: A
authors.initials: A
authors.lastname: Rosenthal
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation; D029721:Drosophila Proteins; D004789:Enzyme Activation; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006801:Humans; D009414:Nerve Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000494:pharmacology; D009447:Neuroblastoma; D051101:Neurturin; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D029721:Drosophila Proteins; C495039:GDNF protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; C495053:NRTN protein, human; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D051101:Neurturin; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; D002118:Calcium